Stephen Konyana ¹ Nadine Teixeira ² Laura Pirjol ² Bukiwe Thwala ² Wandile Nkonyane ² Fungiwe Gxolo ¹ Mireille Porter ² Elizabeth Phillips ³ Rannakoe Lehloenya ² Avumile Mankahla ¹ Jonathan Peter ^2*

• ¹ Walter Sisulu University, Mthatha, South Africa
• ² University of Cape Town, Cape Town, South Africa
• ³ Vanderbilt University Medical Center, Nashville, Tennessee, United States

Cutaneous adverse drug reactions (CADRs) are more prevalent in people with human immunodeficiency virus (PWH).Severe cutaneous adverse drug reactions (SCAR),a subset of CADR, are a significant public health issue in settings endemic for human immunodeficiency virus (HIV) and tuberculosis (TB).Limited data are available on CADR requiring hospitalisation in African settings.The aim of this study is to describe the epidemiology, offending drugs and outcomes of CADRs admitted to a South African tertiary dermatology service.Retrospective folder review was conducted on all CADRs admitted to Nelson Mandela Academic Hospital in Mthatha,between 30 July 2015-15 December 2022.This data was compared to prospective CADR between 3 March 2021-9 April 2024 as part of the Immune-Mediated Adverse Drug Reactions (IMARI) Registry and Biorepository and AFRISCAR consortium.Phenotype and drug causality assessment was performed through RegiSCAR, or Naranjo and/or ALDEN scoring.CADR included 122 cases:89 and 33 in the retrospective and prospective cohorts respectively.The commonest phenotype was Stevens-Johnson syndrome/toxic epidermal necrolysis(SJS/TEN) at 59.8%.Drug reaction with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP) and generalized fixed bullous drug eruption (GBFDE) were other SCAR included.Presentations included typical and atypical SCAR features on Fitzpatrick skin tones of type IV and above.Amongst the retrospective cohort 16.9% of phenotypes were unclassifiable due to lack of photographs.The overall median (IQR) age was 38(25-50) years, 50.8% were male and 60.7% were PWH[median (IQR) CD4 T-cell count of 267 (76-470) cells/mm3].The commonest offending drugs included cotrimoxazole at 24.6% and anti-retroviral therapy (ART) at 13.9%.No offending drug could be identified in 24.7% of the retrospective cohort.The median (IQR) length of hospital stay for SCAR was 13 (8-21) days for the retrospective cohort and 19 (13-28) days for the prospective cohort. The median (IQR) length of hospital stay for non-SCAR was 9 (5-13) days for the retrospective cohort and 11 (9-16) days for the prospective cohort.Typical and atypical presentations of SCAR were represented in this vulnerable South African cohort of predominantly PWH. SJS/TEN was the commonest phenotype, and cotrimoxazole the most frequent offending drug. This data emphasises the need for prospective data collection across a diverse African population for valid SCAR phenotyping and drug causality assessment.